Impact of aliskiren treatment on urinary aldosterone levels in patients with type 2 diabetes and nephropathy: an AVOID substudy.

INTRODUCTION: Aldosterone blockade reduces albuminuria in diabetic patients with chronic kidney disease (CKD), and improves prognosis in chronic heart failure. This study assessed the effects of direct renin inhibition with aliskiren in combination with losartan and optimal antihypertensive therapy on urinary aldosterone, plasma renin activity (PRA) and plasma renin concentration (PRC).

MATERIALS AND METHODS: In the AVOID study, 599 patients with type 2 diabetes, hypertension and nephropathy received 6 months aliskiren (150 mg force titrated to 300 mg once daily after 3 months) or placebo added to losartan 100 mg and optimal antihypertensive therapy. Urinary aldosterone excretion, PRA and PRC were measured at baseline and after 24 weeks in a prespecified subset of 133 patients.

RESULTS: Aliskiren added to losartan provided reductions from baseline in urinary aldosterone compared with adding placebo (-24% vs. -4%, p = 0.017) at week 24. There was no significant difference between the aliskiren and placebo groups in the proportion of patients with aldosterone breakthrough (aliskiren 35%, placebo 46%, p = 0.199). Aliskiren treatment reduced PRA by 90% at 24 weeks and increased PRC by 328%.

CONCLUSIONS: Adding aliskiren to recommended renoprotective treatment with losartan and optimal antihypertensive therapy provided significant reductions in urinary aldosterone excretion which may attenuate decline in kidney function.